Hectograph process and solvent



HECTOGRAPH PROCESS AND SOLVENT No Drawing. Application December 24, 1956Serial No. 630,047

6 Claims. (Cl. 101149.4)

This invention relates to a novel solvent composition for use inhectograph, and related processes, and to a hectograph process utilizingsuch solvent.

In the hectograph process, also called the spirit duplieating system,the image is formed in reverse on a master by transfer from acarbon-type sheet, coated with a composition containing a highproportion of a water and spirit soluble dye, such as crystal violet,Victoria green, Victoria blue and the like. The image transfers from themaster to copy sheets, the surfaces of which have been wetted with analcohol or alcohol and water combination, upon contact, as between acompression cylinder and a printing plate mounted in a rotary duplicateing machine. The highly volatile solvents permit the production ofalarger number of copies and provides formore rapid drying of the copysheet to reduce setoff and smear. In the spirit duplicating systems, thedyestuff is preferably contained in a coating, such as in a carbon sheetfor transfer in mirror image onto the printing master by the applicationof force, or the like. However, various modifications of the process areknown; for instance, that disclosed in Klimkowski U. S. Patent No.2,634,677, wherein a master sheet is provided having one dyestuficomponent-e. g., a stabilized diazo dye intermediate, or a coupler, andthe dyestufr image is formed on the master from a carbon sheet by meansof pressure, as by typing, which transfers to the master the otherdyestufi componente. g., a coupling component or diazoamine, and the dyeimage is formed on the master by coupling thereon. Final copies are thenmade by contacting the master with a copy sheet, which has beenmoistened with a solvent for the dyestulf, so that a portion of the dyetransfers to the copy sheet and gives final copy thereon.

In such hectograph systems, the solvents normally employed formoistening the copy sheet have been the lower alcohols, methanol andethanol; or mixtures thereof, with small amounts of water. Various othersolvents, particularly glycol-type solvents, such as ethylene glycol,propylene glycol, Cellosolve (ethylene glycol monoethyl ether), methylCellosolve (ethylene glycol monomethyl ether), Carbitol (diethyleneglycol monoethyl ether), methyl Carbitol (diethylene glycol monomethylether), and the like, have been used, since they are somewhat bettersolvents for the dyestuffs than ethanol. They are, however, lessvolatile, and such glycol-type solvents, particularly, ethylene glycol,and the lower alkyl (methyl and ethyl) ethers of ethylene glycol anddiethylene glycol, are normally used in less amounts than the ethanol ormethanol in the solvent, since if they are used in too great an amount,due to their low volatility, the copy sheet is still apt to be slightlymoist, when it emerges from the duplicating machine, with the resultthat the dye transferred thereto may smear, or otherwise transfer. Inaddition, various volatile solvents, particularly acetone, arefrequently included in the hectograph transfer liquid, in order tohasten drying. In order to reduce the innited States Patent R 2,862,444Patented Dec. 2, 1958 flammability of the alcohol base of the hectographtransfer liquid, volatile chlorinated solvents, such as methylenechloride, are frequently included in the formulation of hectographtransfer liquids and function with the dual purpose, both to reduceflammability; and due to their volatility, hasten drying. Suchchlorinated solvents are relatively poor solvents for the dyestuffs,and, as a result, relatively weak copies are frequently obtained whenthey are included in the transfer liquid.

I have now found that, by incorporating a small amount of butyrolactone,in prior art hectograph transfer solvents, the infiammability of theprior art solvents, which consist largely of methanol, or ethanol, isappreciably reduced, and, at the same'time, improved copies areobtained. Improvement of the copies is particularly outstanding when thebutyrolactone is added to a solvent containing a chlorinatedhydrocarbon.

The amount of butyrolactone, which I have found to be useful inhectograph transfer solvents is about 10% butyrolactone, by weight,based on the total solvent; and the preferred amount of butyrolactone isin the range of 7 to 15%, by weight, of the total solvent, as withinthese ranges substantially improved copies are obtained, the copiesbeing much denser at the start, of the run, and the total run beingabout the same as when any given transfer fluid is used, which does notcontain butyrolactone. Somewhat higher amounts of butyrolactone, up to20%, by weight, of the total solvent can be used if extremely densecopies are desired at the start of the run. However, when the amount ofbutyrolactone increases above 15%, it appears that too much dyetransfers at the start of the run, so that-the total number of clearcopies which can be obtained is somewhat reduced.

The other components of the solvent of the present,

invention are those commonly employed in the art, the material beingethanol, or methanol, which may contain permissible additions ofethylene glycol-type solvents, and permissible additions of volatilechlorinated hydrocarbon solvents, and/ or other volatile solvents, suchas acetone, to expedite drying; and/or volatile chlorinated solvents toreduce the flammability of the solvent.

In order to fully illustrate the present invention, the followingspecific examples are given:

Example 1 A solvent was prepared, having by weight the followingcomposition:

parts methanol, 10 parts Cellosolve, 10 parts butyrolactone. Thiscomposition was employed as the solvent in a commercial hectographmachine, and it was found that much denser copies Were obtained with itat the start of the run, and density and sharpness maintained up to 70copies and, essentially, the same total number of clear copies wereobtained as when a solvent consisting of 89 parts methanol and 11 partsCellosolve was used. Similar results were obtained when a solventcontaining ethanol, in place of methanol, in the above formulation wasused.

Example 2 A solvent was prepared having by weight the followingcomposition:

10 parts acetone, 45 parts methylene chloride, 35 parts ethanol, 10parts butyrolactone. This composition was employed as a transfer postingliquid, and gave excellent copies, which were much denser than thoseobtained using a commercial transfer liquid having thefollowingcompositions:

10 parts acetone, 55 parts ethylene chloride and 35 parts ethanol.

It will be understood .that the foregoing examples are illustrative onlyof the composition of the present invention, and that it has been foundthat butyrolactone is a useful'additive to a wide variety ofcommercially available hectograph transfer solvents, of undisclosedspecific composition, but containing-substantial mounts of ethanol, ormethanol, and containing: as additives, such products as ethyleneglycol-type solvents, or acetone, and/or volatile, chlorinatedvhydrocarbon solvents. Broadly, therefore, the present invention isdirected to a hectograph transfer solvent having an .alcohol basecontaining preferably from 7 to 15%, and, permissibly, up to 20%, byweight, of butyrolactone.

I claim:

1. In a hectograph process wherein copies areproduced by pressingamaster sheet having adyestutfimage thereonagainst a copy .sheet, atleast one of said sheets being moistened with a solvent for the dyestuffon said master sheet whereby a portion .of the .dyestufl transfers tothe copy sheet and the image on said master sheet is reproduced on thecopy sheet; the improvement which comprises employing as said solvent ahectograph solvent composition having a lower alkanol base andcontaining butyrolactone as an essential ingredient in an amount equalto 7 to 20% of the total weightof said solvent.

2. In a hectograph process wherein copies are produced by pressing amaster sheet having a dyestufi image thereon against a copy sheet, atleast one of said sheets being moistened with a solvent for the dyestulfon said master sheet whereby a portion of the dyestuif transfers to thecopy sheet and the image on said master sheet is reproduced on the copysheet; the improvement'which comprises employing as said solvent athectograph solvent composition having a lower alkanol base andcontaining butyrolactone as an essential ingredient in an amount equalto 7 to 15% of the total weight of said solvent.

3. In a hectograph process whereincopies are produced by pressing amaster sheet having a dyestufi image thereon against a copy sheet, atleast one of said sheets being moistened with a solvent for the dyestuffon said master sheet whereby a portion of the dyestufi transfers to thecopy sheet and the image on said master sheet is reproduced on the copysheet; the improvement which comprises employing as said solvent ahectograph solvent composition having a lower alkanol base andcontaining butyrolactone as an essential ingredient in an amount equalto about 10% of the total weight of said solvent.

4. In a hectograph process wherein copies are produced by pressing amaster sheet having a dyestuif image thereon against a copy sheet, atleast one of said sheets being moistened with a solvent for the dyestulfon said master sheet and the image on said master sheet is reproduced onthe copy sheet; the improvement whichcomprises employing as saidsolvent'a hectograph solvent composition having as a base a mixture of alower alkanol and a volatile chlorinated hydrocarbon and containingbutyrolactone as an essential ingredient in an amount equal to 7 to 20%of the total weight of the solvent.

5. A solvent for use in the hectograph process consisting essentially ofa mixture of a lower alkanol, a glycol solvent selected from the groupconsisting of ethylene and propylene glycol and lower alkyl ethersthereof and butyrolactone, said .butyrolactone comprising from 7 to 20%by weight of the total solvent,'and the lower alkanol comprising morethan 50% of the remainder of said solvent.

6. A non-flammable solvent for use in the hectograph process consistingessentially of a mixture of a lower alkanol, a glycol solvent selectedfrom the group consisting of ethylene and propylene glycol and loweralkyl ethers thereof, and a volatile chlorinated hydrocarbon and'butyrolactone, said butyrolactone comprising from 7 to 20% by weight ofthe total solvent.

References Cited in thefileof this patent UNITED STATES PATENTS 12,254,469 Bjorksten Sept. 2, 1941

1. IN A HECTOGRAPH PROCESS WHEREIN COPIES ARE PRODUCED BY PRESSING AMASTER SHEET HAVING A DYESTUFF IMAGE THEREON AGAINST A COPY SHEET, ATLEAST ONE OF SAID SHEETS BEING MOISTENED WITH A SOLVENT FOR THE DYESTUFFON SAID MASTER SHEET WHEREBY A PORTION OF THE DYESTUFF TRANSFERS TO THECOPY SHEET AND THE IMAGE ON SAID MASTER SHEET IS REPRODUCED ON THE COPYSHEET; THE IMPROVEMENT WHICH COMPRISES EMPLOYING AS SAID SOLVENT AHECTOGRAPH SOLVENT COMPOSITION HAVING A LOWER ALKANOL BASE ANDCONTAINING BUTYROLACTONE AS AN ESSENTIAL INGREDIENT IN AN AMOUNT EQUALTO 7 TO 20% OF THE TOTAL WEIGHT OF SAID SOLVENT.